BBC Sport has reported that the Cherries will pay £10.7m, with the player joining on a four-year contract under manager Eddie Howe. Diego Rico is expected to arrive in the UK within the next 24 hours to agree to personal terms and undergo a medical before officially signing on.
Howe will be delighted that he managed to secure the left-back despite Bundesliga interest, as Rico reportedly preferred a move to the Premier League. Having made 51 appearances in La Liga with Leganes, Rico posted the highest number of interceptions per game (2.9) in the league last season.
Los Pepineros finished 14 points ahead of relegation, with Rico playing a key role in the club's success. He's a gifted crosser with a knack for blocking the ball, although he needs to improve his passing game and ball handling.
It will be interesting to see how Rico will make the change from the largely technical La Liga to the much more aggressive Premier League, and whether he can make the difference for Bournemouth as they seek to better last season's 12th place finish.
Rico will be Bournemouth's second transfer of the summer, after signing David Brooks from Sheffield United.